Sensor systems comprising auxiliary articles

ABSTRACT

A sensor system for detecting a property of or within an absorbent article may comprise an absorbent article and an auxiliary article.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of, and claims priority under 35U.S.C. § 120 to, U.S. patent application Ser. No. 13/483,463, filed onMay 30, 2012, which claims the benefit, under 35 USC § 119(e), of U.S.Provisional Application Nos. 61/493,092, 61/493,095, and 61/493,100,each filed on Jun. 3, 2011, and each of which are herein incorporated byreference in their entirety.

FIELD

In general, embodiments of the present disclosure relate to sensors foruse with absorbent articles. In particular, embodiments of the presentdisclosure relate to auxiliary articles comprising sensors for use withabsorbent articles.

BACKGROUND OF INVENTION

The art discloses many different types of sensors that are integral withan absorbent article (e.g., placed internal of the garment-facing layeror fixed to interior or exterior surfaces of the garment-facing layer).One of the problems with designs having an internal sensor is that mostare throw away sensors, i.e. the sensor is a single-use design disposedwithin the absorbent article primarily because it is undesirable toreuse them once they become contaminated with fecal waste and urine.Such an approach can be expensive given the need to incorporate a sensorinto every absorbent article e.g., diaper. In addition, products thatrely on an electrical circuit as the means for indication on the insideof the product can also expose the wearer to low voltage electricalcurrent.

In addition, accessing sensors disposed on the interior surface of thegarment facing layer for reuse can also be difficult. Alternatively, thesensor may be placed external of the garment facing layer, but stillintegral with the absorbent article. One of the problems with a sensorfixed to the external surface of the garment facing layer is creating ameans for locating the sensor appropriately and then holding orattaching the sensor to the garment facing layer. Such an approach doesnot address the expense of integrating a sensor into every diaper.

One may eliminate these problems by orienting the sensor externally ofthe article in or on an auxiliary article. One of the challenges,however, with this approach is sensing the property of interest fromoutside the absorbent article. Thus, it is one goal of the invention tolocate the sensor in an auxiliary article in communication with theexternal surface of the garment facing layer, liquid impermeable portionof the absorbent article and to design the absorbent article (e.g., thecore, garment facing layer, etc.) to functionally communicate with thesensor.

Another problem with locating the sensor on the interior of theabsorbent article is the need to create every absorbent article with asensor or a place to hold the sensor. This can become very costly. Thus,it is a goal to use the auxiliary article is to offer a sustainablereusable sensor solution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a pant-type auxiliary article with a sensor in thefront, according to embodiments of the present disclosure.

FIG. 1B illustrates a pant-type auxiliary article with a sensor in theback, according to embodiments of the present disclosure.

FIG. 1C illustrates a pant-type auxiliary article with a plurality ofsensors, according to embodiments of the present disclosure.

FIG. 2A illustrates a front-fastenable auxiliary article with a sensorin the front, according to embodiments of the present disclosure.

FIG. 2B illustrates a front-fastenable auxiliary article with a sensorin the back, according to embodiments of the present disclosure.

FIG. 2C illustrates a front-fastenable auxiliary article with aplurality of sensors, according to embodiments of the presentdisclosure.

FIG. 3 illustrates a portion of an auxiliary article with a sensorhaving a first sensing area and a second sensing area, according toembodiments of the present disclosure.

FIG. 4A is an inside plan view illustrating a front-fastenable wearableabsorbent article.

FIG. 4B is an inside plan view illustrating a pant-type wearableabsorbent article.

FIG. 4C is an inside plan view illustrating a feminine pad absorbentarticle.

FIGS. 5A-C illustrate an inductive-type sensor, according to embodimentsof the present disclosure.

FIGS. 6A-D illustrate a capacitive-type sensor, according to embodimentsof the present disclosure.

FIGS. 7A-C illustrate an ultrasonic-type sensor, according toembodiments of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure illustrate various auxiliaryarticles comprising various sensors which may be used with variousabsorbent articles to make a sensor system.

Auxiliary Article Structure

The auxiliary article may be a durable, washable, reusable garmentdesigned to fit over an absorbent article. The auxiliary article may bemade of various materials, including rayon, nylon, polyester, variouspolyolefins, spandex, cotton, wool, flax, or combinations thereof.

The auxiliary article may comprise the sensor between two of its layers.A pocket may be formed in or on the inner or outer surface of theauxiliary article. A window may be formed through one or more of thelayers of the auxiliary article to provide for better communicationbetween the sensor and the absorbent article.

The sensor may be discrete from or integral with the auxiliary article.The auxiliary article may comprise sensors that can sense variousaspects of the absorbent article associated with insults of bodilyexudates for example urine and/or BM (e.g., the sensor may sensevariations in temperature, humidity, presence of ammonia or urea,various vapor components of urine and feces, changes in moisture vaportransmission through the absorbent articles garment-facing layer,changes in translucence of the garment-facing layer, color changesthrough the garment-facing layer, etc.). Additionally, the sensors maysense components of the urine, such as ammonia or urea and/or byproductsresulting from reactions of these components with the absorbent article.The sensor may sense byproducts that are produced when urine mixes withother components of the absorbent article (e.g., adhesives, agm, etc.).The components or byproducts being sensed may be present as vapors thatpass through the garment-facing layer. It may also be desirable to placereactants in the diaper that change state (e.g. color, temperature,etc.) or create a measurable byproduct when mixed with urine. The sensormay also sense changes in pH, pressure, odor, the presence of gas,blood, a chemical marker or a biological marker or combinations thereof.

The sensor may removably be integrated with the auxiliary article withhook and loops fasteners, adhesives, thermal bonds, mating fastenerslike snaps or buttons, or may be disposed in pockets, recesses or voidspaces built into the auxiliary article, or combinations thereof. Manyof these integration means enable removal of and/or attachment of thesensor from or to the auxiliary article. The auxiliary article may bedesigned to receive an absorbent article for example an insert. Examplesof such auxiliary article chassis that may be desired are disclosed inU.S. Pat. No. 7,670,324 and U.S. Pub. Nos. 2010-0179500, 2010-0179496,2010-0179501, 2010-0179502, and 2010-0179499.

FIGS. 1A-2C illustrate acceptable auxiliary articles, each with one ormore sensors. For clarity, FIGS. 1A-2C do not illustrate all details ofthe sensors or of the auxiliary articles. Each sensor and/or auxiliaryarticle in FIGS. 1A-2C can be any embodiment of the present disclosure.

FIG. 1A illustrates an outside perspective view of a front 101 and aside 103 of a pant-type auxiliary article 100A formed for wearing. Thepant-type auxiliary article 100A may include a waist opening 107, a legopening 108, an exterior surface 106, and an interior (absorbentarticle-facing) surface 109. The auxiliary article 100A may include alongitudinally oriented sensor 131 disposed in the front 101.

Throughout the present disclosure, a reference to a pant-type auxiliaryarticle can refer to an embodiment that is side-fastenable or to anembodiment without fasteners. A reference to a pant-type auxiliaryarticle refers to an article having preformed waist and/or leg openings.Thus, each embodiment of an auxiliary article of the present disclosurethat is described as pant-type can be configured in any of these ways,as will be understood by one of ordinary skill in the art.

FIG. 1B illustrates an outside perspective view of a side 103 and a back105 of a pant-type auxiliary article 100B formed for wearing. Thepant-type auxiliary article 100B may include a waist opening 107 and aleg opening 108. Auxiliary article 100B may include a longitudinallyoriented sensor 135 in the back 105.

FIG. 1C illustrates an outside plan view of a pant-type auxiliaryarticle 100C laid out flat. The auxiliary article 100C may include afront 101 and a back 105, separated by a lateral centerline 116.

In FIG. 1C, a longitudinal centerline 113 and the lateral centerline 116provide lines of reference for referring to relative locations of theauxiliary article 100C. When a first location 112 is nearer to thelongitudinal centerline 113 than a second location 111, the firstlocation 112 can be considered laterally inboard to the second location111. Similarly, the second location 111 can be considered laterallyoutboard from the first location 112. When a third location 115 isnearer to the lateral centerline 116 than a fourth location 114, thethird location 115 can be considered longitudinally inboard to thefourth location 114. Also, the fourth location 114 can be consideredlongitudinally outboard from the third location 115.

A reference to an inboard location, without a lateral or longitudinallimitation, refers to a location of the auxiliary article 100C that islaterally inboard and/or longitudinally inboard to another location. Inthe same way, a reference to an outboard location, without a lateral orlongitudinal limitation, refers to a location of the auxiliary article100C that is laterally outboard and/or longitudinally outboard fromanother location.

Inboard and outboard can also be understood with reference to a centerof an auxiliary article. The longitudinal centerline 113 and the lateralcenterline 116 cross at a center 119 of the auxiliary article 100C. Whenone location is nearer to the center 119 than another location, the onelocation can be considered inboard to the other location. The onelocation can be inboard laterally, or longitudinally, or both laterallyand longitudinally. The other location can be considered outboard fromthe one location. The other location can be outboard laterally, orlongitudinally, or both laterally and longitudinally.

FIG. 1C includes arrows indicating relative directions for laterallyoutboard 111 relative to 112, laterally inboard 112 relative to 111,longitudinally outboard 114 relative to 115, and longitudinally inboard115 relative to 114, each with respect to the auxiliary article 100C.Throughout the present disclosure, a reference to a longitudinaldimension, measurement, line, or direction refers to a dimension,measurement, line, or direction that is substantially or completelyparallel to the longitudinal centerline 113 and a reference to a lateraldimension, measurement, line, or direction refers to a dimension,measurement, line, or direction that is substantially or completelyparallel to the lateral centerline 116. The terminology for describingrelative locations, as discussed above, is used for auxiliary articlesthroughout the present disclosure. This terminology can also besimilarly applied to various other absorbent articles, as will beunderstood by one of ordinary skill in the art.

The auxiliary article 100C may include a number of sensors in variousexemplary locations and orientations. The auxiliary article 100C mayinclude a longitudinally oriented sensor such as sensor 131 and 135,along the longitudinal centerline 113 in the front 101 and/or back 105.The front 101 and/or back 105 may include at least one angled sensorsuch as sensors 132, 134, 136 and 138 oriented at an angle between thelongitudinal centerline 113 and the lateral centerline 116. Theauxiliary article 100C may include one or more laterally orientedsensors such as sensors 133 and 137 along the lateral centerline 116.

In the auxiliary article 100C, the sensors may be oriented substantiallyradially out from the center 119. However, in addition to the locationsand orientations illustrated in FIG. 1C, a sensor of the presentdisclosure can be disposed in various alternate locations andorientations relative to an absorbent article. As an example, a sensorcan be disposed in a pant-type auxiliary article at a location relativeto a pee point for a wearer of the absorbent article.

The pant-type auxiliary article may comprise stretchable materials,extensible materials, elastically extensible materials or combinationsthereof disposed at or adjacent the waist and leg openings to providethe extension necessary for application and body conforming fit in use.The pant-type auxiliary article may further comprise and overallstretchable, extensible or elastically extensible layer forming thatprovides a snug fit of the auxiliary article to the absorbent article.

FIG. 2A illustrates an outside perspective view of a front 201 and aside 203 of a front-fastenable auxiliary article 200A formed forwearing. The front-fastenable auxiliary article 200A may include a waistopening 207 and a leg opening 208. The absorbent article 200A mayinclude a longitudinally oriented sensor 231 disposed in the front 201.

While the present disclosure refers to front-fastenable auxiliaryarticles, the present disclosure also contemplates alternate embodimentsof absorbent articles, as described herein, wherein the auxiliaryarticles are rear-fastenable. Thus, each embodiment of an absorbentarticle of the present disclosure that is described as front-fastenablecan also be configured to be rear-fastenable.

FIG. 2B illustrates an outside perspective view of a side 203 and a back205 of a front-fastenable auxiliary article 200B formed for wearing. Thefront-fastenable auxiliary article 200B may include a waist opening 207and a leg opening 208. The auxiliary article 200B may include alongitudinally oriented sensor 235 in the back 205.

FIG. 2C illustrates an outside plan view of a front-fastenable auxiliaryarticle 200C laid out flat. The auxiliary article 200C may include afront 201, a back 205, a longitudinal centerline 213, and a lateralcenterline 216, an exterior surface 206, and an interior (absorbentarticle-facing) surface 209.

The auxiliary article 200C may include a number of sensors in variousexemplary locations and orientations. The auxiliary article 200C mayinclude longitudinally oriented sensors such as sensors 231 and 235,along the longitudinal centerline 213 in the front 201 and/or back 205.The front 201 and/or back 205 may include angled sensors such as sensors232, 234, 236 and 238 oriented at an angle between the longitudinalcenterline 213 and the lateral centerline 216. The auxiliary article200C may include laterally oriented sensors such as sensors 233 and 237along the lateral centerline 216.

In the auxiliary article 200C, the sensors may be oriented substantiallyradially out from the center 219. However, in addition to the locationsand orientations illustrated in FIG. 2C, a sensor of the presentdisclosure can be disposed in various alternate locations andorientations in an auxiliary article. As an example, a sensor can bedisposed in a front-fastenable auxiliary article at a location relativeto a pee point and/or the anus of a wearer of the article.

FIG. 3 illustrates an outside plan view of a portion 308 of an auxiliaryarticle 300 laid out flat. In various embodiments, the auxiliary article300 can be a pant-type auxiliary article or a front-fastenable auxiliaryarticle. In FIG. 3, outside edges of the portion 308 are broken lines,since the portion 308 is illustrated as separate from the rest of theauxiliary article 300. For reference, FIG. 3 illustrates a center 319 ofthe auxiliary article 300 and arrows indicating relative directions foroutboard 317 and inboard 318 for the auxiliary article 300.

The portion 308 of the auxiliary article 300 may include a sensor 320.The sensor 320 may be disposed offset from the center 319. In variousembodiments, one or more parts of a sensor can be disposed near, at, oroverlapping a center of an auxiliary article. For example, a singlesensing area can extend from a front of an auxiliary article, throughthe center of the auxiliary article, to the back of the auxiliaryarticle.

The sensor 320 may include an inboard end 322 and an outboard end 323.The sensor 320 has an overall sensor length 321, measured along thesensor 320 from the inboard end 322 to the outboard end 323. The sensor320 may have an overall shape that is substantially elongated andsubstantially rectangular. The sensor 320 may have a substantiallyuniform width along the entire overall sensor length 321. It may bedesirable that the sensor, or at least a portion of the sensor, has abending stiffness of less than about 1000 N/m, 600 N/m, or 400 N/m (asdetermined by ASTM D 790-03) to keep it from irritating the wearer. Itmay alternatively or additionally be desirable to design the sensor, ora portion of the sensor, to have a bending modulus (N/m2) of less than2.0E+09, 1.0E+08, or 1.0E+06.

In various embodiments a sensor can have an overall shape that is moreor less elongated. In some embodiments, all or part of a sensor may belinear, curved, angled, segmented, or any regular or irregular geometricshape (such as a circle, square, rectangle, triangle, trapezoid,octagon, hexagon, star, half circle, a quarter circle, a half oval, aquarter oval, a radial pattern, etc.), a recognizable image (such as aletter, number, word, character, face of an animal, face of a person,etc.), or another recognizable image (such as a plant, a car, etc.),another shape, or combinations of any of these shapes. Also, in variousembodiments, an indicator can have varying widths over all or part ofits length.

The sensor 320 may include one or more sensing areas for example, afirst sensing area 340 and a second sensing area 360. In variousembodiments, a sensor can include three or more sensing areas.

The first sensing area 340 may include a first area inboard end 342, afirst area outboard end 343, and a first area overall length 341measured along the first sensing area 340 from the first area inboardend 342 to the first area outboard end 343. The first sensing area 340may have an overall shape that is substantially elongated andsubstantially rectangular. The first sensing area 340 may have asubstantially uniform width along the entire first area overall length341. However, in some embodiments, an sensing area can have variousshapes and various widths over all or part of its length, as describedabove in connection with the sensor.

In addition to the first sensing area 340, the sensor 320 may include asecond sensing area 360. In the embodiment of FIG. 3, the second sensingarea 360 is outboard 317 from the first sensing area 340. The secondsensing area 360 may include a second area inboard end 362, a secondarea outboard end 363, and a second area overall length 361 measuredalong the second sensing area 360 from the second area inboard end 362to the second area outboard end 363. In the embodiment of FIG. 3, thesecond area overall length 361 is less than the first area overalllength 341. In some embodiments, a second area overall length can beequal to a first area overall length or greater than a first areaoverall length.

The second sensing area 360 may have an overall shape that issubstantially elongated and substantially rectangular. The second visualfullness sensing area 360 may have a substantially uniform width alongthe entire second area overall length 361.

Absorbent Article

The absorbent article may be one for personal wear, including but notlimited to diapers, training pants, feminine hygiene products,incontinence products, medical garments, surgical pads and bandages,other personal care or health care garments, and the like. Variousmaterials and methods for constructing absorbent articles such asdiapers and pants are disclosed in U.S. Pub. Nos. 2011-0041999,2010-0228211, 2008-0208155, and 2009-0312734.

FIGS. 4A-4C illustrate various absorbent articles. For clarity, FIGS.4A-4C do not illustrate all details of the absorbent articles.

FIG. 4A is an inside plan view of a front-fastenable wearable absorbentarticle 412A. The present disclosure contemplates that an absorbentarticle that is configured to be front-fastenable can also be configuredto be rear fastenable or side-fastenable.

The front-fastenable wearable absorbent article 412A may include awearer-facing layer 413A, a garment-facing layer 415A, and an absorbentmaterial 414A. The absorbent material 414A is disposed between thewearer-facing layer 413A and the garment-facing layer 415A.

The wearer-facing layer 413A is a layer of one or more materials thatform at least a portion of an inside of the front-fastenable wearableabsorbent article and faces a wearer when the absorbent article 412A isworn by the wearer. In FIG. 4A, a portion of the wearer-facing layer413A is illustrated as broken-away, in order to show the garment-facinglayer 415A. A wearer-facing layer is sometimes referred to as atopsheet. The wearer-facing layer 413A is configured to be liquidpermeable, such that bodily fluids received by the absorbent article412A can pass through the wearer-facing layer 413A to the absorbentmaterial 414A. In various embodiments, a wearer-facing layer can includea nonwoven material and/or other materials as long as the materials areliquid permeable over all or part of the wearer facing layer.

The absorbent material 414A is disposed subjacent to the wearer-facinglayer 413A and superjacent to the garment-facing layer 415A, in at leasta portion of the absorbent article 412A. In some embodiments, anabsorbent material of an absorbent article is part of a structurereferred to as an absorbent core. The absorbent material 414A isconfigured to be liquid absorbent, such that the absorbent material 414Acan absorb bodily fluids received by the absorbent article 412A. Invarious embodiments, an absorbent material can include cellulosic fibers(e.g., wood pulp fibers), other natural fibers, synthetic fibers, wovenor nonwoven sheets, scrim netting or other stabilizing structures,superabsorbent material, foams, binder materials, adhesives surfactants,selected hydrophobic materials, pigments, lotions, odor control agentsor the like, as well as combinations thereof, The absorbent structuremay comprise one or more storage layers and one or more surge managementlayers. A pair of containment flaps, elasticated leg cuffs, may form aportion of the interior surface of the absorbent assembly for inhibitingthe lateral flow of body exudates.

The garment-facing layer 415A is a layer formed of one or more materialsthat form at least a portion of an outside of the front-fastenablewearable absorbent article and faces a wearer's garments when theabsorbent article 412A is worn by the wearer. A garment-facing layer issometimes referred to as a backsheet. The garment-facing layer 415A isconfigured to be liquid impermeable, such that bodily fluids received bythe absorbent article 412A cannot pass through the garment-facing layer415A. In various embodiments, a garment-facing layer can include anonporous film, a porous film, a woven material, a non-woven fibrousmaterial or combinations thereof. The outer cover may also bestretchable, extensible, and in some embodiments it may be elasticallyextensible or elastomeric. The garment-facing layer 415A may also bevapor permeable and yet liquid impervious.

FIG. 4B is an inside plan view of a pant-type wearable absorbent article412B. The present disclosure contemplates that, a model of an absorbentarticle that is configured to be pant-type can be configured to beside-fastenable or formed into a pant without fasteners, as will beunderstood by one of ordinary skill in the art.

The pant-type wearable absorbent article 412B may include awearer-facing layer 413B, a garment-facing layer 415B, and an absorbentmaterial 414B, which are each generally configured in the same manner asthe like-numbered elements in the embodiment of FIG. 4A.

FIG. 4C is an inside plan view of a feminine pad absorbent article 412C.The feminine pad absorbent article 412C may include a wearer-facinglayer 413C, a garment-facing layer 415C, and an absorbent material 414C,which are each configured in a manner similar to the like-numberedelements in the embodiments of FIGS. 4A and 4B.

Sensor Structure

The sensors of the present disclosure may form a part of a sensor systemcapable of monitoring urine and/or fecal insults. The system that maytake on a variety of configurations which are determined by the means inwhich the presence of bodily exudates for example urine and/or feces aredetected. After detection of urine and/or feces, the system may inform acaregiver and/or a child by generating a notification. The notificationmay be and auditory signal, an olfactory signal, a tactile signal or avisual signal. It is understood that the system may comprise a devicefor sending a wireless signal to a remote receiver which may in turnresult in an auditory signal, visual signal, tactile signal or othersensory signal and/or combinations thereof.

Manufacturing the sensor independent of the primary disposable absorbentarticle enables utilization of more expensive components and delivery ofmore sophisticated sensor technology. For example, internal sensorsand/or sensors that are part of the absorbent article may require abuilt in power source that needs to last through the storage, shelf-lifeand usage of the absorbent article it is incorporated into. Not tomention, that integrated sensors can introduce significant cost. Tooffset cost, more simple sensors may be utilized but the functionalityand reliability of such cheap sensors would suffer. Stand alone sensorsdisposed exteriorly of the absorbent article do not have theselimitations and could include a means for replacing the power supply orcould be rechargeable.

The sensor may be washable and thus created in a water-tight casing orcoating capable of withstanding temperatures of greater than about 185°F., or greater than about 200° F.

Various sensors may be used, including inductive, capacitive, ultrasonic, optical, moisture, humidity, chemical, temperature,electromagnetic and combinations thereof.

Thermal Sensor

The sensor of the present disclosure may sense incontinent events bymeasuring changes associated with the incontinent event. One of theproperties of the absorbent article that may be sensed is temperaturechange of the article associated with introduction of urine or fecesassociated with an incontinence event. Typical diaper temperaturesbefore urine loading range from about 80 to about 90 degrees Fahrenheit.A urine or fecal insult introduces exudates that are at bodytemperature, typically 98.6 Fahrenheit, which can be detected throughthe garment-facing layer of the article. It has been shown that diapertemperature will over time equilibrate into the range of from about 90to about 92 degrees Fahrenheit after some period of time. Measuring theincontinent event thermally can not only provide an indication of theevent itself, but the temperature profile may be used to determine corecapacity, and/or size of the insult itself, i.e., amount of urine. Thesensor system of the present disclosure may also use the incontinentevent as a trigger to review the properties of the wearer and/or thearticle being monitored before and during the incontinent event. Changesin these properties may show a pattern that can then be used to predictwhen subsequent incontinent events are likely to occur.

Inductive Sensor

An inductive sensor may be used. Referring generally to FIGS. 5A-C, theinductive sensor may work with a LC-oscillator. This sensor can work bythe conductive fluid (urine) damping the oscillating circuit such thatthe output voltage decreases. Measured data may be gathered from anattached device that detects an change of voltage during urination.

The LC-oscillator may generate a sine wave oscillation at a resonancefrequency and an electromagnetic field outside the coil, whereinresonace frequency is f0=(2Π*√(LC))31 1. A conductive material withinthis field will dampen the oscillating circuit by inducing eddy currentsinside the material. Conductive material could be metal, carbon,electrically conductive plastics or electrically conductive fluids likesaltwater or urine. The damping of the oscillating circuit decreases theoutput voltage, this change will be detected and evaluation electronicsgenerate an output signal indicative of the change.

Frequency range of the inductive sensor may be from about 10 kHz toabout 100 MHz depending on frequency, coil size and distance. Detectiondistance may be from about 1 to about 20 mm. Coil dimensions may have adiameter from about 5 mm to about 50 mm. Coil geometry may be asolenoid, copper wire coil with or without a core, or may be a flat,pancake coil made of copper wires or may be printed copper coil on PCB(Printed Circuit Board), or as conductive ink or color printed on paperor plastic foil.

Capacitive Sensor

A capacitive sensor may be used. Referring generally to FIGS. 6A-D, acapacitive sensor may work with an RC-oscillator. The sensor works byfluid changing the dielectric and thus increases the capacity of theelectrode arrangement. Dependent on the sensor capacity the frequencyand the amplitude of the RC-oscillator changes. Measured data may begathered from an attached device that detects a change of frequency andamplitude during urination.

The capacitive sensor defines the active sensor area. A change of thedielectric medium decreases or increases the capacity of the electrodearrangement and changes the output signal of the oscillation unit.

Capacitive sensors are able to detect solid materials and fluids,independent of the conductivity of the material. The sensitivity andalso the detection distance of the capacitive sensor is related to sizeof the active sensor area and the material and size of the body thatshould be detected.

Ultra Sonic Sensor

An ultra sonic sensor may be used. Referring generally to FIGS. 7A-C,ultrasonic sensors generate high frequency sound waves in a frequencyrange from 20 kHz up to 1 GHz.

For distance measurement and object detection they measure the signalrun time between transmitted pulse and the echo which is received backby the sensor. Some ultra sonic sensors use separate transmitter andreceiver components while others combine both in a single piezoelectrictransceiver.

Ultra sonic sensors will work with most of surfaces and also withboundary surfaces between different fluids or gases. The technology islimited by the shapes of surfaces and the density or consistency of thematerial, but with adapted frequencies and output power is it possibleto detect difficult surfaces or materials. Another way to increase thesensor density is to apply variable scan frequencies.

Inside a medium with known density and/or sonic velocity the distancecan be calculated as following:

calculation of the distance x based on run time measurement

v=x/t t=signal run time

x=v*t x=distance

v=inside the medium (in air 346 m/sec)

travel distance of the signal=2 times distance to the object:

2x=v*t

x=(v*t)/2

In case of a single piezoelectric transducer is used the minimumdetectable distance is limited by the recovery time of the piezo. Therecovery time depends on piezo size, frequency and on electronics.

The measured time difference between transmitted pulse and receivedpulse is proportional to the distance to the next boundary surface. Theemitted power and the transmitter frequency must be configured topenetrate the dry absorbing material and also the garment facing layer.

Optical Sensor

An alternative sensor approach of the present disclosure sensesincontinent events by measuring optical change of the absorbent articleassociated with a urine or fecal incontinence event. The sensor maysimply measure optical changes as urine or feces contact thegarment-facing layer of the absorbent article, e.g., change in colorassociated with the yellow urine or brown feces. Alternatively, thearticle may comprise a material placed adjacent the garment-facing layerthat reacts with the urine of feces insult to change color and providethe optical indication necessary for sensing. In yet another alternativeof an optical sensing system the outer cover may comprise a materialthat changes in translucency when wet, thereby allowing an inner layerto show through creating the optically measurable change. It should beappreciated that these optical changes are desirably reversible afterthe insult, for example, once the liquid has been absorbed by theabsorbent core. Alternatively, it may be desirable that the opticalproperties change to a measurable degree with each subsequentincontinent event. Measuring the incontinent event optically can notonly provide an indication of the event itself, but the duration of theoptical change particularly in a reversible change structure can providean indication of core capacity, product dryness and/or size of theinsult itself, e.g. amount of urine. Sensor systems of the presentdisclosure may also use the incontinent event as a trigger to review theproperties of the wearer and/or the article monitored before and duringthe incontinent event. Changes in these properties may show a patternthat can then be used to predict when subsequent incontinent events arelikely.

In an alternative embodiment, a simple absorbent sheet may become darkerwhen liquid is introduced and as liquid is absorbed back into theabsorbent core the simple absorbent sheet may become lighter in color.As stated above, it is preferred that the optical changes are eithercyclic in nature, i.e., on and off or are progressive in nature, i.e.changing from one level of intensity to another with each loading. Theseapproaches, cyclic and progressive will enable to sensors to distinguishwhen a loading has occurred and provide reliable indication.

Chemicals and Properties Sensed

In yet another alternative embodiment, sensors of the present disclosuremonitor incontinent events by measuring changes associated with anincontinent event. One of the properties of the absorbent article thatmay be monitored is transmission of a specific gas or vapor through thearticle outer cover. The creation of the gas or vapor may be associatedwith a urine and/or fecal incontinence event. Microporous, breathableouter covers have the ability to pass gases and/or vapors through thepores of the outer cover itself. The monitoring involves one or morereactants that create or generate a gas or vapor when contacted by urineand/or feces. It should be appreciated that the selective gas and/orvapor transmission through the outer cover is desirably cyclic, i.e.,lower once the liquid has been absorbed and high when free liquid ispresent. The magnitude of the cyclic nature of the reactant needs onlybe sufficient for reliable sensing of the event. Measuring theincontinent event via moisture vapor transmission can not only providean indication of the event itself, but the moisture vapor transmissionprofile or threshold values may be used to determine core capacity,product dryness and/or size of the insult itself, e.g., amount of urine.Further, the incontinent event may act as a trigger to review theproperties of the wearer and/or the article being monitored before andduring the incontinent event. Changes in these properties may showpatterns which can then be used to predict when subsequent incontinentevents are likely.

Communication

There are a number of acceptable orientations for placing sensors in oron the auxiliary article to ensure the desired sensing of theenvironment within the absorbent article. For instance, an aperture orabsorbent free zone may be created in the core of the absorbent articleso that fecal waste or urine are more readily disposed against thegarment-facing layer and thereby provide a strong enough stimulus (e.g.,chemical, visual, etc.) that is detectable by the sensor. For thispurpose, use of a substantially air felt free core may be desirable.Examples of acceptable air felt free cores are disclosed in U.S. Pat.Nos. 5,562,646, 7,750,203, 7,744,576 and U.S. Pub. Nos. 2008/0312617,2008/0312619, and 2004/0097895. Alternatively, the sensor may comprise amechanical fastener, e.g., a hook-like material that can engage with theouter surface of the product, nonwoven or loop material to hold thesensor in place. In an alternative approach the sensor may comprise amagnet designed to pull the sensor into contact with the externalsurface of the absorbent article. In such a design the article maycomprise a thin piece of magnetically compatible material.

Sensors of the present disclosure may be designed to predict when anincontinent event may happen. For example, in one embodiment, the sensormay monitor a property of an absorbent article while the article isbeing worn. The sensor may determine a change in the property of theabsorbent article wherein the change is indicative of an incontinentevent of the wearer. Further, the sensor may predict conditionsindicative of a subsequent incontinent event based on the change in aproperty. The sensor may make predictions by comparing a series ofincontinent events and conditions present at, during or before theincontinent events, and by determining patterns in the conditionspresent at, during or before the incontinent events. Further, the sensormay provide an insult notification to inform a caregiver and/or thewearer of the presence of an insult in the absorbent article.

As said above, one of the advantages to having a sensor that isremovably attachable to an absorbent article or having a sensor in anauxiliary article is the ability to use more sophisticated (which arenormally more expensive) sensor systems. It may be desirable to placetwo or more sensors (sensor A and sensor B) in the absorbent articlesuch that sensors A and B detect and communicate separate events (e.g.,sensor A-fever and sensor B-urine).

It may also be desirable to use three or more sensors, where sensor A isdesigned to send signals to an external device (e.g., cell phone), andwhere sensors B and C are designed to send signals to sensor A. Evenmore sophisticated are systems where sensor A, before it communicateswith the external device, first checks the status of sensors B and C.Alternatively, it is forseen that some sensor systems may be designedsuch that sensor A, when it receives a signal from sensor B, then checksthe status of sensor C before sending a signal to the external device.

In other embodiments, each of sensors A, B, and C are able to sendsignals to the external device and do so once a certain stimulus isdetected. Additionally, sensors may be used to send signals to anexternal device to confirm that an event has not happened.

Moisture Vapor Transmission

In yet another alternative embodiment, the sensors of the presentdisclosure may sense incontinent events by measuring changes in moisturevapor transmission through the absorbent article garment-facing layer.Microporous, breathable garment-facing layers have the ability to passmoisture vapor through the pores of the layer itself. The rate oftransmission is highly dependent on the distance the liquid is from thesurface of the microporous material. Typical microporous materialsexhibit significantly higher “wet cup” moisture vapor transmission rates(liquid directly on the surface of the material) than “dry cup” moisturevapor transmission rates (high humidity on one side low humidity on theother). Therefore, such microporous materials will have a highermoisture vapor transmission rate during and immediately after theincontinence event, especially for urine and watery feces, than duringthe remainder of the wearing time, when the diaper is dry or once theabsorbent materials have contained all of the free liquid. It may bedesirable to use a breathable garment-facing layer for the purpose ofmeasuring WVTR. WVTRs of garment-facing layers of the present disclosuremay range from about 500 to about 8,000, from about 1,000 to about6,000, or from about 2,000 to about 4,000 g/m²/24 hours (as determinedby ASTM E96).

The sensor system of the present disclosure may monitor a secondproperty which is indicative of an intake of a substance by the wearersuch a liquid, a solid, or a drug. For example this property may be datathe wearer or caregiver may enter via a wireless handheld device orcomputer comprising a keyboard, mouse or touchpad indicating that thewearer has consumed food and/or liquids or has been given a drug. Apattern may show that at a given time after eating and/or drinking anincontinent event may occur.

The sensor system may predict conditions indicative of a subsequentincontinent event a number of ways. The sensor system may compare thechanges in the first and the second properties that are being monitoredand compare them with known patterns predictive of incontinent events.Alternatively the sensor system may look for individual incontinentevents as indicated by the first property and then looked to changes inthe second property which preceded the incontinent event. Upon findingan instance of a change in the second property followed by anincontinent event, the sensor system may then compare other incontinentevents for a similar cause and effect relationship. Multiple secondproperties may be compared to find more complex relationships andpatterns.

Sustainability

There is a growing desire to utilize more sustainable absorbentarticles. It is too costly and too wasteful to incorporate a sensor intoeach article, and to throw it away with each absorbent article change.Instead of throwing away hundreds or thousands of disposable sensors perwearer, a single external sensor in an auxiliary article may be reused.The sensor may be oriented in a washable, reusable auxiliary article.

Another advantage of using a single sensor outside the absorbent articleis that the sensor may be used with any absorbent article, includingbrand, type (taped, pull-on diapers, training pants, etc.), size (e.g.,infant to adult).

Internal sensors and/or sensors that are part of the absorbent articlemay require a built in power source that needs to last through thestorage and shelf-life of the absorbent article it is incorporated into.Sensors that are removable from the absorbent article and/or auxiliaryarticle may be set in a recharging base or may have replaceablebatteries.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests,or discloses any such invention. Further, to the extent that any meaningor definition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A sensor system for detecting a property of orwithin an absorbent article, comprising: an absorbent article comprisinga garment facing layer and an absorbent assembly; an auxiliary articlecomprising a sensor; wherein the sensor is capable of being orientedexternally adjacent the garment facing layer when the auxiliary articleis fitted over the absorbent article, and wherein the auxiliary articledoes not comprise an absorbent assembly; wherein the sensor is notphysically attached to the absorbent article; and wherein the sensor isconfigured to sense a first change of a first property within theabsorbent article; and wherein the sensor is capable of predicting anincontinent event.
 2. The sensor system of claim 1, wherein the firstchange of the first property is selected from the group consisting oftemperature changes, humidity changes, density changes, optical changes,acoustical changes, chemical changes, changes in thickness of theabsorbent article, changes in material properties of the absorbentarticle, and combinations thereof.
 3. The sensor system of claim 1,wherein a portion of the sensor has a bending modulus less than 2.0E+09N/m2.
 4. The sensor system of claim 1, wherein the sensor is capable ofcomparing the first change of the first property with a pattern ofproperty changes.
 5. The sensor system of claim 1, wherein the sensor iscapable of comparing the first change of the first property withprevious incontinent events of a wearer of the sensor system.
 6. Thesensor system of claim 1, wherein the sensor is capable of predictingthe incontinent event by comparing a series of past incontinent events.7. The sensor system of claim 1, wherein the first change is used by thesensor to predict an incontinent event of a wearer of the sensor system.8. The sensor system of claim 1, wherein the sensor system comprises asecond sensor capable of sensing a second change of a second property.9. The sensor system of claim 6, wherein the sensor is capable ofpredicting the incontinent event by comparing the series of pastincontinent events to the first change of the first property.
 10. Thesensor system of claim 1, wherein the sensor system is capable ofproviding an insult notification to a cell phone to inform a caregiverand/or a wearer of the sensor system of the presence of an insult in theabsorbent article.
 11. The sensor system of claim 1, wherein the sensoris discrete from the auxiliary article and is attached to an interiorsurface of the auxiliary article.
 12. The sensor system of claim 1,wherein the sensor is integral with the auxiliary article.
 13. Thesensor system of claim 1, wherein the absorbent core is air felt free.14. The sensor system of claim 8, wherein the first property isdifferent than the second property.
 15. The sensor system of claim 1,wherein the sensor is disposed between two layers of the auxiliaryarticle.
 16. The sensor system of claim 15, wherein the auxiliaryarticle comprises a pocket configured to receive the sensor.
 17. Asensor system for detecting a property of or within an absorbentarticle, comprising: an absorbent article comprising a garment facinglayer of a vapor permeable, liquid impermeable backsheet and anabsorbent assembly comprising an absorbent core; an auxiliary articlecomprising a first sensor and a second sensor, wherein the auxiliaryarticle is a distinct article from the absorbent article, the auxiliaryarticle adapted to fit over the absorbent article, and wherein theauxiliary article does not comprise an absorbent assembly; wherein theauxiliary article comprises front and back waist regions, and a crotchregion; wherein the first and second sensors are oriented such that atleast one of the first and second sensors overlap the crotch region andat least one of the first and second sensors overlap at least one of thefront and back waist regions; wherein the first and second sensors arenot physically attached to the absorbent article when the auxiliaryarticle is fitted over the absorbent article and when the sensor systemis in use; and wherein the first and second sensors are capable ofsensing different property changes selected from the group consisting oftemperature changes, humidity changes, density changes, optical changes,acoustical changes, chemical changes, changes in thickness of theabsorbent article, changes in material properties of the absorbentarticle, and combinations thereof.
 18. The sensor system of claim 17,wherein the first sensor is capable of sensing optical changes.
 19. Thesensor system of claim 18, wherein the second sensor is capable ofsensing chemical changes.
 20. The sensor system of claim 17, wherein thefirst sensor is capable of sensing humidity changes.